Which of the following is a sign of nail fungus?

Discoloration and thickening of the nail are strong indicators of nail fungus. When fungal infections occur, they often lead to changes in the color of the nail, which can appear yellow, brown, or even greenish. This discoloration typically comes alongside thickening as the nail structure may become distorted due to the infection. Fungal conditions can also cause the nail to become brittle or crumble, but the combination of discoloration and thickening is a classic and clear sign of nail fungus. Understanding these signs is crucial for nail technicians, as recognizing such conditions helps in providing proper care and advice to clients.